Synopsis

Description

The ldap_open() function initializes an LDAP session and also opens a connection to
an LDAP server before it returns to the caller. Unlike ldap_open(), ldap_init() does not
open a connection to the LDAP server until an operation, such as
a search request, is performed.

The ldap_open() function is deprecated and should no longer be used. Call ldap_init()
instead.

A list of LDAP hostnames or an IPv4 or IPv6 address can
be specified with the ldap_open() and ldap_init() functions. The hostname can include a port
number, separated from the hostname by a colon (:). A port number included
as part of the hostname takes precedence over the port parameter. The ldap_open()
and ldap_init() functions attempt connections with LDAP hosts in the order listed and
return the first successful connection.

Parameters

These functions support the following parameters.

host

The hostname, IPv4 or IPv6 address of the host that runs the LDAP server. A space-separated list of hostnames can also be used for this parameter.

port

TCP port number of a connection. Supply the constant LDAP_PORT to obtain the default LDAP port of 389. If a host includes a port number, the default parameter is ignored.

Return Values

The ldap_open() and ldap_init() functions return a handle to an LDAP session that
contains a pointer to an opaque structure. The structure must be passed to
subsequent calls for the session. If a session cannot be initialized, the functions
return NULL and errno should be set appropriately.

Various aspects of this opaque structure can be read or written to
control the session-wide parameters. Use the ldap_get_option(3LDAP) to access the current option values
and the ldap_set_option(3LDAP) to set values for these options.

Examples

Example 1 Specifying IPv4 and IPv6 Addresses

LDAP sessions can be initialized with hostnames, IPv4 or IPv6 addresses, such as
those shown in the following examples.